Reduced cell death and improved cell membrane integrity in rice under salinity by root associated bacteria

Abstract

Salt stress causes oxidative damage and cell death in plants. In this study, root associated bacteria Pseudomonas aeruginosa and Bacillus megaterium were inoculated in two rice cultivars, named Dhandi (salt-tolerant) and GR 11 (salt-sensitive), to mitigate detrimental effects of salt stress. We aimed to investigate the protective effects of Pseudomonas aeruginosa and Bacillus megaterium on paddy exposed to salt stress (150 mM NaCl) under controlled environmental growth condition. Salt stress in plants increased reactive oxygen species (ROS) accumulation, lipid peroxidation, DNA fragmentation and apoptosis-like cell death. Both bacterial strains effectively decreased ROS accumulation, lipid peroxidation, suppressed DNA fragmentation and apoptosis-like cell death in the presence of severe salt stress. We found that P. aeruginosa and B. megaterium significantly suppressed the increment of membrane permeability induced by salinity. It was concluded that both P. aeruginosa and B. megaterium provide protection against NaCl-induced cell death by decreasing levels of ROS accumulation and lipid peroxidation as well as improvement of membrane integrity.